CELPIP Reading Part 3 · Reading for Information · set 5 of 10

Zebra Mussels in Our Lakes

A CELPIP Reading Part 3 practice set (Reading for Information): the full text, 9 questions and the answer key with an explanation for each answer. No sign-up needed. For real practice, answer every question before you look at the key.

The task

SMALL SHELLS, BIG TROUBLE: ZEBRA MUSSELS IN CANADIAN WATERS A. Zebra mussels are small freshwater shellfish, usually no larger than a fingernail, named for the striped pattern on their shells. They are native to lakes and rivers in parts of eastern Europe and western Asia and were first discovered in the Great Lakes in the late 1980s. Scientists believe they arrived in the ballast water of ocean-going ships, which take on water in one port to stay balanced and release it in another, sometimes thousands of kilometres away. Once established, the mussels spread rapidly through connected rivers and canals. Their discovery surprised many researchers, who had not expected a species from such a distant region to do so well here. Since then, they have been found in many inland lakes in Ontario and Quebec. B. Several features make zebra mussels unusually successful invaders. A single female can release enormous numbers of eggs in a season, and the young drift freely in the water for several weeks before settling on almost any hard surface. Adults attach themselves with strong threads to rocks, docks, boat hulls and even other shellfish. Because they have few natural predators in North America, their populations can grow to densities of thousands per square metre, forming thick crusts that cover the lake bottom and smother native species. A closely related species, the quagga mussel, has spread in a similar way and can live in even deeper and colder water. C. The effects reach far beyond the water's edge. The mussels clog the intake pipes of water treatment plants and power stations, forcing operators to spend large sums on cleaning and prevention. Their sharp shells cut the feet of swimmers on beaches. They also change entire ecosystems. Each mussel filters plankton from the water, and as a result, infested lakes often become noticeably clearer. While clear water may look healthy, it means less food for native fish and allows sunlight to reach deeper, encouraging the growth of weeds and algae on the bottom. Beaches can become littered with empty shells, which give off an unpleasant smell as they decay. D. Once zebra mussels are established in a large lake, removing them is practically impossible, so prevention is the main strategy. Provinces in western Canada, where most lakes remain free of the species, have set up inspection stations along highways where boats must be checked before they enter. Boaters everywhere are urged to clean, drain and dry their vessels and equipment before moving from one body of water to another. Even a small amount of water left in a boat's engine or bait bucket can carry tiny larvae to a new lake, where a new population may take hold. Anyone who finds mussels attached to a boat or dock in a new area is asked to report it to provincial authorities so that the problem can be dealt with quickly.

Read the following passage.
Decide which paragraph, A to D, has the information given in each statement below. Select E if the information is not given in any of the paragraphs.

Questions: 9
Time: 10 minutes
Practice set: 5 of 10

Questions and answer key

For each statement, choose the paragraph (A to D) that has the information, or E if no paragraph gives it.

1Water that looks cleaner can actually be a sign of damage to the ecosystem.
Answer: Paragraph C
Paragraph C says infested lakes "become noticeably clearer" and that "While clear water may look healthy, it means less food for native fish." Paragraph D discusses preventing spread, not water clarity.
2Young mussels float in the water before fixing themselves to something solid.
Answer: Paragraph B
Paragraph B says "the young drift freely in the water for several weeks before settling on almost any hard surface." Paragraph D mentions "tiny larvae" but only as something carried in boats.
3The species probably reached North America in water carried by ships.
Answer: Paragraph A
Paragraph A states "Scientists believe they arrived in the ballast water of ocean-going ships." Paragraph D also mentions water in boats, but it concerns spreading between lakes, not the original arrival.
4Boats travelling by road may be stopped and examined in some parts of the country.
Answer: Paragraph D
Paragraph D says western provinces "have set up inspection stations along highways where boats must be checked." Paragraph C mentions costs to operators, not inspections.
5Because few animals eat the mussels, their numbers can grow very large.
Answer: Paragraph B
Paragraph B says "Because they have few natural predators in North America, their populations can grow to densities of thousands per square metre." Paragraph C mentions food for native fish, which is a different issue.
6Chemical treatments have successfully wiped out the mussels in some small ponds.
Answer: E (not given in any paragraph)
Paragraph D says removal from a large lake is "practically impossible," but no paragraph mentions chemicals or success in small ponds.
7Facilities that take water from lakes face extra expenses because of the mussels.
Answer: Paragraph C
Paragraph C states that the mussels "clog the intake pipes of water treatment plants and power stations, forcing operators to spend large sums." Paragraph B mentions docks and hulls, but not costs.
8Even a little water left in equipment can spread the species to new places.
Answer: Paragraph D
Paragraph D warns that "Even a small amount of water left in a boat's engine or bait bucket can carry tiny larvae to a new lake." Paragraph A describes spread through "rivers and canals," not equipment.
9People enjoying the shoreline can be hurt by the mussels.
Answer: Paragraph C
Paragraph C says "Their sharp shells cut the feet of swimmers on beaches." Paragraph A describes the size and pattern of the shells, but not injuries.

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